Are you only believing what you read in the media or do you know people that actually work at Amazon? The fact that Amazon employees in a warehouse rejected unionization speaks volumes. And I know plenty of Amazon engineers that love working there.
To put it in perspective, there may be employees that hate working at Amazon, but there are also 100,000 employees. If only 10% of the employees hated working there, that's still 10,000 employees. But a 90% satisfaction rate for any company is amazingly high.
I've only once had an employer I would describe as kind. Even then, it was but for the generosity of an aberrant manager, and not a commercial institution.
In most low-skill positions (especially the ones which favor physical labor over soft-skills), you are a body to be instrumentalized until you either leave leave or are disposed of. That's the reality of most work. Retention is as high as it needs to be to ensure continuous operations, and employee happiness is either incidental or primarily a slogan. The human element is made to be as irrelevant as the market will allow.
The Amazon Warehouse workers I've known have described it as warehouse work. Little better or worse in their experience than working at any other distribution center, though some centers are naturally likely to be ran more poorly than others.
To put it in perspective, there may be employees that hate working at Amazon, but there are also 100,000 employees. If only 10% of the employees hated working there, that's still 10,000 employees. But a 90% satisfaction rate for any company is amazingly high.